CMK-3 nanostructured carbon: Effect of temperature and time carbonization on textural properties and H2 storage

Abstract

CMK-3 carbons were synthesized varying the carbonization conditions and studying the effect of the templates calcined at different temperatures. The textural characterization of different SBA-15 templates calcined at 350, 450, and 550?°C shows a variation of the specific surface area below 10%. Based on the results, the SBA-15 obtained at 350?°C (the more affordable condition) was used as the final template for the CMK-3 synthesis. The results show that varying the time (from 2 to 6?h) and the temperature (from 600 to 900?°C) on the carbonization step, the textural, structural, and morphological properties of the carbons do not vary in a meaningful way. Thus, a CMK-3 carbon synthesized (using as template an SBA-15 calcined at 350?°C) obtained at 600?°C during 2?h was chosen to be used as adsorbent in hydrogen storage in order to stablish the relationship between the textural properties and its performance. Regarding the hydrogen storage, capacities of 15?mg H₂ g^?1 (1.5% w/w), and up to 28?mg H₂ g^?1 (2.8% w/w) were obtained at 1 and 10?bar, respectively. At high pressure, an important influence of the large micropores and narrow mesopores on the hydrogen adsorption was found.